Objective  To investigate lung injury effect of sodium arsenite (NaAsO₂) in rats and the expression and significance of inflammatory markers associated with the injury.

  Methods  Thirty-two Wistar rats were randomly divided into four groups according to body weight: a control group and three groups with 4-month gavage administration of NaAsO₂ at dosages of 2.5, 5, and 10 mg/kg per day. The expression of Clara cell secretory protein (CC16), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in lung tissue and serum were detected with immunofluorescence assay and enzyme-linked immunosorbent assay (ELISA). Pearson correlation analysis was adopted to assess the association between expressions of the markers in lung tissues and serum.

  Results  After 90 days′ treatment, the body weight of the rats exposed to moderate- and high-dose NaAsO₂ decreased significantly (P < 0.05). For the rats with NaAsO₂ treatment, the expression of CC16 in lung tissue and serum of reduced significantly (P < 0.05) and the expression of CC16 in lung tissue was positively correlated with that in serum (r = 0.89, P < 0.05); while, the expression of MMP-9 in lung tissue and serum increased significantly (P < 0.05) and MMP-9 expression in lung tissue was positively correlated with that in serum (r = 0.50, P < 0.05); the ratio of MMP-9/TIMP-1 expression in lung tissue was positively correlated with the ratio of the expressions in serum (r = 0.38, P < 0.05).

  Conclusion  Arsenic exposure can induce lung injury in rats and expressions of inflammatory markers in lung tissue and serum are associated with the development of arsenic-induced lung injury.